Question: "What is the difference between infer and imply?"
While infer and imply are words that may sound similar, they do have different meanings. This wasn't always the case, as authors from Shakespeare to Austen often used infer where we now use imply. As late as 1976 the Concise Oxford Dictionary still treated the words as interchangeable, but usage now makes the words distinct. Let's look at each in turn.
Imply means "to involve or indicate by inference, association, or necessary consequence rather than by direct statement"; "to contain potentially"; or "to express indirectly". So when something is implied there is no direct statement made. For example:McKay turned up his nose as he was handed the final piece of equipment. "I've seen better in a fifth grade science class."
"Do you mean to imply that I don't know what I'm doing?" Zelenka responded, raising his voice in protest.
Rodney McKay doesn't come right out and say that he doesn't think Dr. Zelenka knows what he's doing. Instead he expresses that opinion indirectly by saying that he's seen children do better. So when we imply, we are letting someone know what we think but are being subtle in doing so.
Infer, on the other hand, means "to derive as a conclusion from facts or premises"; "guess, surmise"; "to evolve as a normal outcome of thought"; "to point out"; or "suggest, hint". The significant difference here is that while imply is about saying something indirectly, infer is about drawing a conclusion given some information. We can see this if I modify our first example:McKay turned up his nose as he was handed the final piece of equipment. "I've seen better in a fifth grade science class."
"How dare you suggest that I don't know what I'm doing!" Zelenka responded, immediately inferring that the quality of his work was being questioned.
It's possible to think about this in terms of the sender and receiver of a message. The sender can imply something, but the receiver can only infer something. McKay is the sender of the communication above since he is the one making the statement, and in doing so he is implying that the equipment he's been handed is below his standards. Zelenka is the receiver of the message -- he's listening to what McKay has said, so he reads between the lines and is able to infer, or draw, a conclusion.
Infer doesn't have to be related to a conversation, though. For example:"In looking at the data, I was able to infer that I can significantly improve the success rate of the adoption of the ATA gene," Beckett said excitedly.
Nobody has said anything to Beckett. He's been doing research and has reached a conclusion that he's excited about. But he has drawn a conclusion, so infer is an appropriate word to use. Any time something is being determined or derived, it is being inferred. And that isn't limited to a conversation, which is the case with imply because to imply there must be communication.
What's a good way of remembering the difference? If something is implied, there must be communication. But you can infer any time that you are drawing a conclusion.
Sources:
Bryson's Dictionary of Troubled Words, p103
Imply at m-w.com
Infer at m-w.com
Learn the Difference between Imply and Infer